Semiconductor structures including a gallium nitride material component and a silicon germanium component

Abstract

The invention provides semiconductor structures that include a gallium nitride material component and a silicon germanium component, as well as methods of forming such structures. The gallium nitride material component may be a layer formed on a substrate, or may be the substrate itself. Similarly, the silicon germanium component may be a layer formed on a substrate, or may be the substrate itself. Crack formation within the two components can be limited by matching the thermal expansion rates of the gallium nitride material and the silicon germanium and, thus, inhibiting the generation of thermal stresses within the components. The semiconductor structures may be used in a number of microelectronic and optoelectronic applications, amongst others.

What is claimed is:  
     
         1 . A semiconductor structure comprising: 
 a silicon germanium component; and    a gallium nitride material component.    
     
     
         2 . The semiconductor structure of  claim 1 , wherein the silicon germanium component is a layer.  
     
     
         3 . The semiconductor structure of  claim 2 , wherein the silicon germanium layer is formed on a substrate.  
     
     
         4 . The semiconductor structure of  claim 3 , wherein the silicon germanium layer is formed on a silicon substrate.  
     
     
         5 . The semiconductor structure of  claim 2 , wherein the silicon germanium layer is formed on a silicon germanium substrate.  
     
     
         6 . The semiconductor structure of  claim 1 , wherein the silicon germanium component is a substrate and the gallium nitride component is a layer formed on the silicon germanium substrate.  
     
     
         7 . The semiconductor structure of  claim 1 , wherein the gallium nitride component is a layer.  
     
     
         8 . The semiconductor structure of  claim 7 , wherein the gallium nitride layer is formed on a silicon substrate.  
     
     
         9 . The semiconductor structure of  claim 1 , wherein the gallium nitride component is a substrate and the silicon germanium component is a layer formed on the gallium nitride substrate.  
     
     
         10 . The semiconductor structure of  claim 1 , wherein the gallium nitride material component is in direct contact with the silicon germanium component.  
     
     
         11 . The semiconductor structure of  claim 1 , further comprising an intermediate layer formed between the silicon germanium component and the gallium nitride material component.  
     
     
         12 . The semiconductor structure of  claim 11 , wherein the intermediate layer is compositionally graded.  
     
     
         13 . The semiconductor structure of  claim 2 , wherein the composition of the silicon germanium layer is graded.  
     
     
         14 . The semiconductor structure of  claim 13 , wherein the germanium concentration of the silicon germanium layer is increased in a direction away from the substrate.  
     
     
         15 . The semiconductor structure of  claim 1 , wherein the silicon germanium component has a monocrystalline structure.  
     
     
         16 . The semiconductor structure of  claim 1 , wherein the silicon germanium component has a thermal expansion coefficient within ±25% of the thermal expansion coefficient of the gallium nitride material layer.  
     
     
         17 . The semiconductor structure of  claim 1 , wherein the silicon germanium component comprises a Si x Ge (1−x)  alloy and x is greater than or equal to 0.7.  
     
     
         18 . The semiconductor structure of  claim 17 , wherein the silicon germanium component comprises a Si x Ge (1−x)  alloy and x is greater than or equal to 0.8.  
     
     
         19 . The semiconductor structure of  claim 1 , wherein the gallium nitride material component comprises a Al x In y Ga (1−x−y) N alloy.  
     
     
         20 . The semiconductor structure of  claim 19 , wherein the sum of (x+y) is less than 0.2.  
     
     
         21 . The semiconductor structure of  claim 1 , wherein the gallium nitride material component comprises GaN.  
     
     
         22 . The semiconductor structure of  claim 1 , wherein the gallium nitride material component has a crack level of less than 0.005 μm/μm 2 .  
     
     
         23 . The semiconductor structure of  claim 1 , wherein the gallium nitride material layer forms at least a portion of a device region.  
     
     
         24 . The semiconductor structure of  claim 1 , wherein the structure forms an FET.  
     
     
         25 . The semiconductor structure of  claim 1 , wherein the structure forms an LED.  
     
     
         26 . The semiconductor structure of  claim 1 , wherein the structure forms a laser diode.  
     
     
         27 . The semiconductor structure of  claim 1 , wherein the structure forms a first semiconductor device that includes the silicon germanium component and a second semiconductor device that includes the gallium nitride material component.  
     
     
         28 . The semiconductor structure of  claim 27 , wherein the first semiconductor device is integrated with the second semiconductor device.  
     
     
         29 . A semiconductor structure comprising: 
 a silicon germanium component; and    a gallium nitride material layer formed on the silicon germanium component, the gallium nitride material layer having a crack level of less than 0.005 μm/μm 2 .    
     
     
         30 . A semiconductor structure comprising: 
 a silicon substrate;    a silicon germanium layer formed on the silicon substrate; and    a gallium nitride material layer formed on the silicon germanium layer.    
     
     
         31 . A semiconductor structure comprising: 
 a substrate;    a silicon germanium component formed on the substrate; and    a gallium nitride material component formed on the substrate,    wherein the structure forms a first semiconductor device that includes the silicon germanium component and a second semiconductor device that includes the gallium nitride material component, the first semiconductor device being integrated with the second semiconductor device.    
     
     
         32 . The semiconductor structure of  claim 31 , wherein the silicon germanium component and the gallium nitride component are formed on different portions of the substrate.  
     
     
         33 . A method of forming a semiconductor structure comprising: 
 forming a gallium nitride material layer on a silicon germanium component.    
     
     
         34 . The method of  claim 33 , wherein the silicon germanium component is a substrate.  
     
     
         35 . The method of  claim 33 , wherein the silicon germanium component is a layer and further comprising forming the silicon germanium layer on a substrate.  
     
     
         36 . The method of  claim 33 , wherein comprising forming the silicon germanium layer on a silicon substrate.  
     
     
         37 . The method of  claim 33 , wherein the silicon germanium component has a thermal expansion coefficient within ±25% of the thermal expansion coefficient of the gallium nitride material layer.  
     
     
         38 . A method of forming a semiconductor structure comprising: 
 forming a silicon germanium layer on a gallium nitride component.